Relation of Automatically Extracted Formant Trajectories with Intelligibility Loss and Speaking Rate Decline in Amyotrophic Lateral Sclerosis

Rachelle L. Horwitz-Martin, Thomas F. Quatieri, Adam C. Lammert, James R. Williamson, Yana Yunusova, Elizabeth Godoy, Daryush D. Mehta, Jordan R. Green

Effective monitoring of bulbar disease progression in persons with amyotrophic lateral sclerosis (ALS) requires rapid, objective, automatic assessment of speech loss. The purpose of this work was to identify acoustic features that aid in predicting intelligibility loss and speaking rate decline in individuals with ALS. Features were derived from statistics of the first (F₁) and second (F₂) formant frequency trajectories and their first and second derivatives. Motivated by a possible link between components of formant dynamics and specific articulator movements, these features were also computed for low-pass and high-pass filtered formant trajectories. When compared to clinician-rated intelligibility and speaking rate assessments, F₂ features, particularly mean F₂ speed and a novel feature, mean F₂ acceleration, were most strongly correlated with intelligibility and speaking rate, respectively (Spearman correlations > 0.70, p < 0.0001). These features also yielded the best predictions in regression experiments (r > 0.60, p < 0.0001). Comparable results were achieved using low-pass filtered F₂ trajectory features, with higher correlations and lower prediction errors achieved for speaking rate over intelligibility. These findings suggest information can be exploited in specific frequency components of formant trajectories, with implications for automatic monitoring of ALS.

doi: 10.21437/Interspeech.2016-403

Cite as: Horwitz-Martin, R.L., Quatieri, T.F., Lammert, A.C., Williamson, J.R., Yunusova, Y., Godoy, E., Mehta, D.D., Green, J.R. (2016) Relation of Automatically Extracted Formant Trajectories with Intelligibility Loss and Speaking Rate Decline in Amyotrophic Lateral Sclerosis. Proc. Interspeech 2016, 1205-1209, doi: 10.21437/Interspeech.2016-403

@inproceedings{horwitzmartin16_interspeech,
  author={Rachelle L. Horwitz-Martin and Thomas F. Quatieri and Adam C. Lammert and James R. Williamson and Yana Yunusova and Elizabeth Godoy and Daryush D. Mehta and Jordan R. Green},
  title={{Relation of Automatically Extracted Formant Trajectories with Intelligibility Loss and Speaking Rate Decline in Amyotrophic Lateral Sclerosis}},
  year=2016,
  booktitle={Proc. Interspeech 2016},
  pages={1205--1209},
  doi={10.21437/Interspeech.2016-403}
}